scholarly journals MOLECULAR RINGS AROUND INTERSTELLAR BUBBLES AND THE THICKNESS OF STAR-FORMING CLOUDS

2010 ◽  
Vol 709 (2) ◽  
pp. 791-800 ◽  
Author(s):  
Christopher N. Beaumont ◽  
Jonathan P. Williams
Keyword(s):  
Star Forming ◽  
Molecular Rings

scholarly journals The ALMA Lupus protoplanetary disk survey: evidence for compact gas disks and molecular rings from CN

2019 ◽  
Vol 623 ◽  
pp. A150 ◽  
Author(s):  
S. E. van Terwisga ◽  
E. F. van Dishoeck ◽  
P. Cazzoletti ◽  
S. Facchini ◽  
L. Trapman ◽  
...  
Keyword(s):  
Large Fraction ◽  
Protoplanetary Disks ◽  
Strongly Correlated ◽  
Star Forming ◽  
Disk Size ◽  
Physico Chemical ◽  
Significant Difference ◽  
Chemical Code ◽  
Molecular Rings ◽  
Better Than

Context. The cyanide radical CN is abundant in protoplanetary disks, with line fluxes often comparable to those of 13CO. It is known to be sensitive to UV irradiation of the upper disk atmosphere, with models predicting ring-shaped emission. Aims. We seek to characterize the CN emission from 94 Class-II disks in the Lupus star-forming region, compare it to observations in other regions, and interpret our observations with a grid of models. The CN emission morphology is discussed for two primordial disks, Sz 71 and Sz 98, and is modeled in more detail. Methods. ALMA observed CN N = 3−2 in Lupus disks down to sensitivities better than previous surveys. Models constructed with the physico-chemical code DALI are used to study the integrated fluxes of the disks and resolved emission of CN in disks without (dust) substructures. Results. CN N = 3−2 is bright, and detected in 38% of sources, but its disk-integrated flux is not strongly correlated to either 13CO or continuum flux. Compared to pre-ALMA single-dish surveys, no significant difference in the CN flux distributions in Lupus and Taurus–Auriga is found, although ρ Ophiuchus disks may be fainter on average. We find ring-shaped CN emission with peak radii of ~50 AU in two resolved disks. Conclusions. A large fraction of sources are faint in CN; only exponential gas surface density cutoffs at Rc ≤ 15 AU can reconcile observations with models. This is the first observational evidence of such a compact gas disk population in Lupus. Absolute intensities and the emission morphology of CN are reproduced by DALI models without the need for any continuum substructure; they are unrelated to the CO snowline location. The observations presented here, together with the modeling of these rings, provide a new probe of the structure and conditions in disks, and particularly their incident UV radiation field, if disk size is determined from the data.

Two [Ln4] molecular rings folded as compact tetrahedra

2020 ◽  
Vol 49 (21) ◽  
pp. 7182-7188
Author(s):  
Jorge Salinas-Uber ◽  
Leoní A. Barrios ◽  
Olivier Roubeau ◽  
Guillem Aromí
Keyword(s):  
Weak Interactions ◽  
Molecular Rings

A new highly photo-switchable ligand furnishes supramolecular tetrahedral nanomagnets with Ln(iii) ions (Ln = Dy, Tb). Intramolecular weak interactions define the conformation of the ligand, quenching the photochromic activity.

Far infrared study of the giant star forming complex W 51

2002 ◽  
Vol 4 ◽  
pp. 333-333
Author(s):  
S. K. Ghosh ◽  
D. K. Ojha ◽  
R. P. Verma
Keyword(s):  
Far Infrared ◽  
Infrared Study ◽  
Giant Star ◽  
Star Forming

Evolution of the H2O Maser Emission in the Star-Forming Region S252A

2019 ◽  
Vol 63 (12) ◽  
pp. 1022-1034
Author(s):  
N. T. Ashimbaeva ◽  
P. Colom ◽  
E. E. Lekht ◽  
M. I. Pashchenko ◽  
G. M. Rudnitskii ◽  
...  
Keyword(s):  
Maser Emission ◽  
Star Forming

Spectral Indices of Centimeter Continuum Sources in Star-forming Regions: Implications on the Nature of the Outflow Exciting Sources

1998 ◽  
Vol 116 (6) ◽  
pp. 2953-2964 ◽  
Author(s):  
Guillem Anglada ◽  
Eva Villuendas ◽  
Robert Estalella ◽  
Maria T. Beltrán ◽  
Luis F. Rodríguez ◽  
...  
Keyword(s):  
Spectral Indices ◽  
Star Forming ◽  
Star Forming Regions

A WIYN Lithium Survey for Young Stars in the λ Orionis Star-Forming Region

1999 ◽  
Vol 118 (5) ◽  
pp. 2409-2423 ◽  
Author(s):  
Christopher J. Dolan and Robert D. Mathieu
Keyword(s):  
Young Stars ◽  
Star Forming

On the Structure and Morphology of the “Diffuse Ionized Medium” in Star‐forming Galaxies

1999 ◽  
Vol 515 (1) ◽  
pp. 97-107 ◽  
Author(s):  
Jing Wang ◽  
Timothy M. Heckman ◽  
Matthew D. Lehnert
Keyword(s):  
Star Forming ◽  
Structure And Morphology ◽  
Diffuse Ionized Medium

Bidimensional Spectroscopic Mapping and Chemical Abundances of the Star‐forming Dwarf Galaxy I Zw 18

1998 ◽  
Vol 508 (1) ◽  
pp. 248-261 ◽  
Author(s):  
José M. Vílchez ◽  
Jorge Iglesias‐Páramo
Keyword(s):  
Dwarf Galaxy ◽  
Chemical Abundances ◽  
Star Forming

scholarly journals Diffuse γ-ray emission toward the massive star-forming region, W40

2020 ◽  
Vol 639 ◽  
pp. A80
Author(s):  
Xiao-Na Sun ◽  
Rui-Zhi Yang ◽  
Yun-Feng Liang ◽  
Fang-Kun Peng ◽  
Hai-Ming Zhang ◽  
...  
Keyword(s):  
Cosmic Ray ◽  
High Energy ◽  
Young Star ◽  
Gas Content ◽  
Large Area ◽  
Stellar Cluster ◽  
Production Region ◽  
Star Forming ◽  
Photon Index ◽  
Young Star Clusters

We report the detection of high-energy γ-ray signal towards the young star-forming region, W40. Using 10-yr Pass 8 data from the Fermi Large Area Telescope (Fermi-LAT), we extracted an extended γ-ray excess region with a significance of ~18σ. The radiation has a spectrum with a photon index of 2.49 ± 0.01. The spatial correlation with the ionized gas content favors the hadronic origin of the γ-ray emission. The total cosmic-ray (CR) proton energy in the γ-ray production region is estimated to be the order of 1047 erg. However, this could be a small fraction of the total energy released in cosmic rays (CRs) by local accelerators, presumably by massive stars, over the lifetime of the system. If so, W40, together with earlier detections of γ-rays from Cygnus cocoon, Westerlund 1, Westerlund 2, NGC 3603, and 30 Dor C, supports the hypothesis that young star clusters are effective CR factories. The unique aspect of this result is that the γ-ray emission is detected, for the first time, from a stellar cluster itself, rather than from the surrounding “cocoons”.

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